Clinicopathologic features of hyperplastic/serrated polyposis syndrome in Japan

Surveillance after Endoscopic Resection for Colorectal Tumors: A Comprehensive Review

BACKGROUND

The goal of surveillance after the endoscopic resection of colorectal tumors is to reduce colorectal cancer (CRC) incidence and mortality. Considering the effective use of the limited endoscopic capacity and the cost of surveillance, it is desirable to develop a surveillance program that is as minimal as possible. In Europe (European Society of Gastrointestinal Endoscopy [ESGE]) and the USA (Multi-Society Task Force [MSTF]), after the results of the National Polyp Study (NPS) were established, guidelines were developed that stratified risk based on initial endoscopy, and surveillance programs for each risk group were proposed. More than 10 years later, the "colonoscopy screening and surveillance guidelines" were developed with the basic principle of "aiming for zero CRC deaths during surveillance, bowel preservation, and emphasis on patient quality of life" as the guideline principles in Japan.

SUMMARY

Randomized controlled trials to evaluate the appropriate surveillance intervals after endoscopic resection of colorectal tumors, the NPS, the Nottingham Study, and the Japan Polyp Study (JPS), are summarized. The ESGE, USMSTF, and Japanese guidelines compared low-risk adenoma, high-risk adenoma, advanced neoplasia, piecemeal resection, and serrated lesions by category.

KEY MESSAGES

Surveillance guidelines based on risk stratification were developed in Japan. Guidelines are meaningful only when they are effectively utilized in clinical practice. They must also be revised based on new evidence. It is hoped that new knowledge will be accumulated, especially in Japan, on topics that are currently lacking.

BACKGROUND

The goal of surveillance after the endoscopic resection of colorectal tumors is to reduce colorectal cancer (CRC) incidence and mortality. Considering the effective use of the limited endoscopic capacity and the cost of surveillance, it is desirable to develop a surveillance program that is as minimal as possible. In Europe (European Society of Gastrointestinal Endoscopy [ESGE]) and the USA (Multi-Society Task Force [MSTF]), after the results of the National Polyp Study (NPS) were established, guidelines were developed that stratified risk based on initial endoscopy, and surveillance programs for each risk group were proposed. More than 10 years later, the "colonoscopy screening and surveillance guidelines" were developed with the basic principle of "aiming for zero CRC deaths during surveillance, bowel preservation, and emphasis on patient quality of life" as the guideline principles in Japan.

SUMMARY

Randomized controlled trials to evaluate the appropriate surveillance intervals after endoscopic resection of colorectal tumors, the NPS, the Nottingham Study, and the Japan Polyp Study (JPS), are summarized. The ESGE, USMSTF, and Japanese guidelines compared low-risk adenoma, high-risk adenoma, advanced neoplasia, piecemeal resection, and serrated lesions by category.

KEY MESSAGES

Surveillance guidelines based on risk stratification were developed in Japan. Guidelines are meaningful only when they are effectively utilized in clinical practice. They must also be revised based on new evidence. It is hoped that new knowledge will be accumulated, especially in Japan, on topics that are currently lacking.

Clinicopathological characteristics of colorectal serrated polyposis syndrome (SPS): results of a multicenter study by the SPS Study Group in Japan

BACKGROUND

Serrated polyposis syndrome (SPS), a type of colorectal polyposis characterized by multiple serrated polyps, is associated with a high risk of colorectal carcinoma (CRC). This study aimed to clarify the clinicopathological characteristics of SPS in Japan.

METHODS

We investigated the clinicopathological characteristics of patients with SPS from the "Multicenter Study on Clinicopathological Characteristics of SPS (UMIN 000032138)" by the Colorectal Serrated Polyposis Syndrome (SPS) Study Group. In this study, patients were diagnosed with SPS based on the 2019 World Health Organization (WHO) SPS diagnostic criteria.

RESULTS

Ninety-four patients were diagnosed with SPS in 10 institutions between January 2001 and December 2017. The mean number (± standard deviation [SD]) of resected lesions per patient was 11.3 ± 13.8. The mean age at diagnosis of SPS was 63.3 ± 11.6 years, and 58 patients (61.7%) were male. Eighty-seven (92.6%) and 16 (17.0%) patients satisfied WHO diagnostic criteria I and II, respectively. Nine patients (9.6%) satisfied both criteria I and II. Carcinoma (T1-T4) were observed in 21 patients (22.3%) and 24 lesions. Of the 21 patients with CRC, 19 (90.4%) satisfied diagnostic criterion I, 1 (4.8%) satisfied diagnostic criterion II, and 1 (4.8%) satisfied diagnostic criteria I and II. There was no notable difference in the prevalence of CRC among patients who met diagnostic criterion I, II, and both I and II.

CONCLUSIONS

Patients with SPS have a high risk of CRC and should undergo regular surveillance colonoscopy. Raising awareness of this syndrome is crucial.

Risk of Colorectal Cancer in Serrated Polyposis Syndrome: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Serrated polyposis syndrome (SPS) is characterized by development of numerous serrated lesions throughout the colorectum and increased risk of colorectal cancer (CRC). However, SPS has been an underrecognized CRC predisposition syndrome, and the true risk of CRC in SPS, both overall and in surveillance, is not known. The aim of this systematic review and meta-analysis is to describe the risk of CRC in patients with SPS.

METHODS

Electronic databases were searched on March 25, 2021, for studies describing CRC risk in SPS. Random-effects meta-analysis was performed to assess pooled risk of CRC among SPS patients. Primary outcomes were risk of CRC at time of SPS diagnosis and during surveillance following diagnosis of SPS. Secondary outcomes included risk of CRC prior to diagnosis of SPS and effect of World Health Organization subtype on CRC risk.

RESULTS

Thirty-six studies including 2788 patients with SPS were included in the analysis. Overall risk of CRC in SPS was 19.9% (95% confidence interval [CI], 15.3%-24.5%). CRC risk at the time of diagnosis was 14.7% (95% CI, 11.4%-18.8%), while risk during surveillance was 2.8% (95% CI, 1.8%-4.4%), or 7 cases per 1000 person-years. SPS patients also had a high incidence of history of CRC prior to SPS diagnosis (7.0%; 95% CI, 4.6%-11.7). Subgroup analysis did not reveal any significant differences based on World Health Organization subtype.

CONCLUSIONS

Our meta-analysis demonstrated that patients with SPS have an elevated risk of CRC, which is highest at the time of diagnosis and suggests the importance of early SPS recognition and screening to modify CRC risk. The persistently elevated CRC risk during surveillance supports current guidelines recommending heightened surveillance protocols.

Colonoscopy screening and surveillance guidelines

The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts. These clinical practice guidelines consist of 20 clinical questions and eight background knowledge topics that have been determined as the current guiding principles.

Serrated Polyposis Syndrome in a Single-Center 10-Year Experience

Aims:

Serrated polyposis syndrome is a disease that is often missed in the clinical setting and is associated with colorectal cancer. We investigated the prevalence of SPS and the association between colorectal or other cancers in a 10-year, retrospective data analysis.

Methods:

We reviewed complete colonoscopy data obtained from January 2005 through January 2015 at a health-screening centre. Serrated polyposis syndrome was defined on the basis of the criteria established by the 2010 World Health Organization.

Results:

Of a total of 53.842 consecutive subjects who underwent complete colonoscopy, 12 (0.022%) patients had serrated polyposis syndrome. All of these cases were under-recognized by the endoscopist or referring physician. The mean patient age was 58.6 years; 67% of the patients were men and 33% were women. No serrated polyposis syndrome patients had a first-degree relative with serrated polyposis syndrome, and no serrated polyposis syndrome patients had colorectal cancer. Two cases (17%) had extra-colonic cancers (prostate cancer and thyroid cancer). Eight cases (67%) had a family history of cancer (stomach, breast, lung, pancreas, prostate and colorectal cancer).

Conclusion:

Serrated polyposis syndrome was a rare condition in a 10-year database, and it was diagnosed late in all cases. Serrated polyposis syndrome may be associated with an increased risk of extra-colonic cancer.

Clinical characteristics of patients with serrated polyposis syndrome in Korea: comparison with Western patients

Background/Aims

Serrated polyposis syndrome (SPS) has been shown to increase the risk of colorectal cancer (CRC). However, little is known about the characteristics of Asian patients with SPS. This study aimed to identify the clinicopathological features and risk of CRC in Korean patients with SPS as well as the differences between Korean and Western patients based on a literature review.

Methods

This retrospective study included 30 patients with SPS as defined by World Health Organization classification treated at Samsung Medical Center, Korea, between March 1999 and May 2011.

Results

Twenty patients (67%) were male. The median patient age at diagnosis was 56 years (range, 39–76 years). A total of 702 polyps were identified during a median follow-up of 43 months (range, 0–149 months). Serrated polyps were noted more frequently in the distal colon (298/702, 55%). However, large serrated polyps and serrated adenomas were mainly distributed throughout the proximal colon (75% vs. 25% and 81% vs. 19%, respectively); 73.3% had synchronous adenomatous polyps. The incidence of CRC was 10% (3/30 patients), but no interval CRC was detected. A total of 87% of the patients underwent esophagogastroduodenoscopy and 19.2% had significant lesions.

Conclusions

The phenotype of SPS in Korean patients is different from that of Western patients. In Korean patients, SPS is more common in men, there were fewer total numbers of serrated adenoma/polyps, and the incidence of CRC was lower than that in Western patients. Korean patients tend to more frequently have abnormal gastric lesions. However, the prevalence of synchronous adenomatous polyps is high in both Western and Korean patients.

Clinicopathological characteristics of serrated polyps as precursors to colorectal cancer: Current status and management

Serrated polyps have long been thought to lack malignant potential in the human colorectum. However, identification of the serrated pathway to colorectal cancer based on molecular biology has improved our understanding of the pathogenesis of colorectal cancers. Accordingly, serrated polyps such as traditional serrated adenoma and sessile serrated adenoma/polyps (SSA/P) are now considered to be precursor lesions of the serrated pathway. Recently, serrated polyps were classified into three subtypes, consisting of hyperplastic polyp, SSA/P, and traditional serrated adenoma, according to the World Health Organization classification. It has been suggested that SSA/P in the proximal colon are a precursor lesion of pathogenesis of colorectal cancer and are characterized by BRAF mutation and a CpG island methylator phenotype with or without microsatellite instability. However, SSA/P is more challenging to detect by colonoscopy and is likely to account for some interval cancers, particularly in the proximal colon because it presents flat or sessile, isochroous appearance, and occasionally has a mucous cap. Furthermore, the possibility has been raised that pathologists misclassify SSA/P as hyperplastic polyp. It is important for gastroenterologists to recognize the endoscopic features of serrated polyps to facilitate their detection and removal and also to establish postpolypectomy surveillance guidelines. In this review, we discuss the recent classification of serrated polyps; the molecular characteristics of the serrated pathway; appropriate diagnostic methods using endoscopy, including a new image-enhanced endoscopic technique; and management of these lesions.

Molecular and histologic considerations in the assessment of serrated polyps

CONTEXT : Colorectal cancer is a heterogeneous disease resulting from different molecular pathways of carcinogenesis. Recent data evaluating the histologic features and molecular basis of the serrated polyp-carcinoma pathway have significantly contributed to more comprehensive classifications of and treatment recommendations for these tumors.

OBJECTIVE

To integrate the most recent molecular findings in the context of histologic classifications of serrated lesions and their implications in diagnostic pathology and colorectal cancer surveillance.

DATA SOURCES

Published literature focused on serrated polyps and their association with colorectal cancer.

CONCLUSIONS

Three types of serrated polyps are currently recognized: hyperplastic polyps, sessile serrated adenomas/polyps, and traditional serrated adenomas. The BRAF V600E mutation is one of the most frequent molecular abnormalities identified in hyperplastic polyps and sessile serrated adenomas. In contrast, in traditional serrated adenomas, either BRAF V600E or KRAS mutations can be frequently identified. CpG methylation has emerged as a critical molecular mechanism in the sessile serrated pathway. CpG methylation of MLH1 often leads to reduced or lost expression in dysplastic foci and carcinomas arising in sessile serrated adenomas/polyps.

Clinicopathological Characteristics of Serrated Polyposis Syndrome in Korea: Single Center Experience

Background/Aim. Serrated polyposis syndrome (SPS) is a rare condition characterized by multiple serrated polyps throughout the colon and rectum. The aim of this study was to evaluate the clinicopathological characteristics of SPS in Koreans. Methods. This retrospective analysis of prospectively collected data was performed using information from the endoscopy, clinical records, and pathology database system of Uijeongbu St. Mary's Hospital. Consecutive patients satisfying the updated 2010 World Health Organization criteria for SPS between June 2011 and May 2014 were enrolled. Results. Of the 17,552 patients who underwent colonoscopies during the study period, 11 (0.06%) met the criteria for SPS. The mean age of these patients was 55.6 years. Ten patients (91%) were males. None had a family history of CRC or a first-degree relative with SPS. Seven patients (64%) had synchronous advanced adenoma. One patient had coexistence of SPS with CRC that was diagnosed at the initial colonoscopy. Five patients (45%) had more than 30 serrated polyps. One of the patients underwent surgery and 10 underwent endoscopic resection. Conclusion. The prevalence of SPS in this study cohort was comparable to that in Western populations. Considering the high risk of CRC, correct diagnosis and careful follow-up for SPS are necessary.